Computer pointing devices such as mice and trackballs enable a user to conveniently and efficiently interact with a computer. Mice include a moveable housing and a means, such as a ball or optical sensors, for sensing the movement of the housing in typically two orthogonal directions over a surface. Two signals are produced representative of movement of the housing in the two directions. Movement of the mouse housing in the two directions over the surface is translated into movement of a cursor in two dimensions on a computer screen.
Trackballs include a generally stationary housing with a ball partially enclosed therein. A user rolls the ball in a desired direction, and rotation of the ball on two orthogonal axes is sensed. Two signals are produced representative of rotation of the ball along the two axes. Rotation of the ball along the two axes is translated into movement of the cursor in two dimensions on the computer screen.
Mice and trackballs and similar input devices generally provide for only two positioning signals with corresponding two-dimensional movement of a cursor or other pointer on a computer screen. With increasing sophistication of computer applications, it has become desirable to provide a way for inputting a third positioning signal useful for three-dimensional movement of a cursor or for variably controlling other attributes of objects or data displayed on a computer screen. Such a signal may be termed a "z input" signal because of its use to provide a positioning input along a third or "z" axis. A mechanism for providing a z input may be termed a z-encoder mechanism.
An advantageous way of providing a z-encoder mechanism is through the use of a rotatable wheel button having a rim protruding through the housing of a mouse or other computer input device. The wheel button may be both rotatable and depressable, and a user may rotate the wheel button with or without simultaneously depressing it. The rotational position of the wheel can be sensed to provide a third positioning signal in a mouse or similar input device. The third positioning signal may be used in any desired fashion, such as for controlling cursor movement along a third axis, or for adjusting other attributes of objects or data displayed on a computer screen. The depression of the wheel button may also be sensed by the encoder mechanism to provide a button signal which may also be used in any desired fashion, such as to control or vary the use of the third positioning signal.
In addition to both a button signal and a third positioning signal, wheel button mechanisms desirably provide tactile and even aural feedback to a user, to allow a user to sense depression and rotation of the wheel button.
Previous wheel button mechanisms for computer mice or similar computer input devices have been excessively complex, with relatively large numbers of parts and relatively complicated construction. For wide-spread adoption and use of such mechanisms to be more easily achieved, a simpler, more economical mechanism is needed.
Accordingly, the present invention provides for a computer input device with a simpler, more elegant, more economical wheel button type z-encoder mechanism. The wheel button is supported on an axle or spindle within the housing of the input device. The axle is supported in the housing by spaced-apart axle supports. The axle supports are configured to allow one end of the axle to move in a direction perpendicular to the axis of rotation of the wheel button such that the wheel button may be depressed, tilting the axle sightly. A spring mounted within the housing is arranged to resist depression of the wheel button.
An optical encoder may be positioned on the axle for rotation with the wheel button. A light source and a light sensor may be mounted within the housing so as to sense the motion of the optical encoder to provide a positioning signal. A microswitch may be mounted within the housing, and a switch engager on the axle may be arranged to depress the microswitch when the wheel button is depressed, thereby providing a button signal. A detent mechanism may also be provided on the axle and may engage a detent spring mounted within the housing to provide a segmented feel to the rotation of the wheel button. The size of the segments may be proportioned to the resolution of the optical encoder.
The foregoing and additional features and advantages of the present invention will be more readily apparent form the following detailed description, which proceeds with reference to the accompanying drawings.